Thread: How Much HP Can a B13/B14 LSD Tranny Hold?

To much bench building going on.

Stratton.

I am going to try and dial out some torque to prevent killing the p11 tranny. I am sure at the boost levels I plan to run I will see over 460whp and 390+lbft. thats enough to kill any sr20 tranny quick. I am going to use the same formula that I did on my last car. 1) sprung clutch 2)shock proof heavy 3) place racing motor mounts with solid dog bone 4) welded case 5) good suspension. I will be adding traction bars to the mix just for good measure. I will also perform the no break tranny dance

I am sorry to say but that Unicorn motor/setup would make absolutely no sense. Not for the track or street.

Definitely not from a stock stroked SR20VE. A 16VE would better fit this theory, but still not even close to feasible.

Revving to 10.5k on a 30R (even with a 1.06 hot side) to achieve 500whp, while staying below 250ft lbs/tq? IDC what you do to gradually increase boost with RPM it is not happening.

500whp with 250wheel tq, you will need to run a gigantore turbo on not so much boost... on a 30R I will certainly not believa that of an SR20 unless I see dyna sheet...

besides, I ask because Im curious, what will be the point of having so much whp with so low tq, If you mannage to achieve it

We will just have to agree to disagree then.

..... oh man.

Stratton.

It should be as simple as keeping the boost down to say 15psi and then have the wastegate just slam shut after say 6k rpms and go from there. Its not that hard to do with an ems type system that can do both boost by gear and fully control a boost control solenoid throughout rpm as well. AEM ems should be able to do this. Your standard electronic boost controller would not be able to do this.

Again not that hard and it makes sense. Run 15psi of boost till 6k then hit it hard after. However your torque is still gonna follow behind your hp fairly closely but you make it a much more smooth transistion

The only other option is to run a huge turbo but then you have no power down low and then hits hard up top but keeps your torque down significantly. If you want a 10.5k rpm powerband a huge turbo is the smoothest way to go and yes, it will keep torque down. Because even with the smaller turbo and running low boost until 6k then hitting it hard is still gonna create a nice jolt of torque.

What's wrong, got that aftertaste in your mouth, still?

Apparently you can't read what I said. TORQUE kills, not WHP.

WHP is a PRODUCT of WTQ. So, you should be asking "How much WTQ will break my transmission".

Now back to the regularly scheduled programming. This I agree with 110%, no questions asked. Seen it with my own two eyes, and own two hands/feet.

Lets not drift away from Bryan's question, though. He's not going to kill a B14 LSD transmission with conservative boost on a T28 from say a GTiR. That ALL depends on if Jamie tunes the car, or not.

Mike is saying the MTBF (Mean Time Before Failure) goes down considerably when you are above 170 whp. When it will break is unknown, what is known is that the reliability of the transmission is compromised. After that it comes down to driving behavior and luck.


FYI...I know you guys are talking mostly about sheering gears, but I developed 5th gear pop-out on my original B13 transmission, fixed under extended warranty at 56K. It broke again and got rebuilt with Nissan parts at around 100K. It broke again around 175K.

This is on a DE with simple bolt-ons, not even cams. Compared to this lot? I drive like a grandma in a blue Buick. No street racing ever. Smooth shifts are my goal, always. One (1) time ever on a road course around 172K. Redline Heavy Shockproof. No "hand on the shift-knob" or other bad habits. Prothanes.

My DE-powered experience may be worse than most with the B13 transmission. Some turbo-powered cars may have better luck than I have.

Now I have:

1) B15 transmission
1) Andreas Miko Tranny Saver Bracket
1) Redline fluid, not the heavy shockproof...forgot which one
1) Stage 3 clutch from Greg V

And pre-existing

1) Prothanes
1) Stillen flywheel

I have no faith whatsoever in the p.o.s. B13 transmission holding anything over stock. Further, that "B14 tranny fix" was a lame-ass band-aid and no guarantee of much better reliability.